What we see in reality is that companies tend to consolidate into bigger and bigger conglomerates.

It's easy to see why.

As small companies compete, you naturally get market leaders. As these companies get larger they become more efficient at producing goods and services. They invest in mass production techniques in order to produce goods more cheaply than their competitors. They buy raw materials at cheaper prices because they buy in bulk. They expand specialization amongst their workforce. The bigger they get, the easier it is to make money.

When two market leaders merge they achieve massive economies of scale. This forces others to merge in order to compete, leading to ever greater concentration. Monopolies often buy their rivals.

It's not a matter of being "evil", it's just a natural outcome of capitalism. If they don't, a competitors will.